The overall objective of this research project is to determine contitioned neural responses associated with drug dependency. Although a number of conditioning models of addiction have been formulated, as yet there has been almost no examination of neural correlates of these models. In chronic rat studies, a conditioning procedure is used with stimuli to one forepaw delivered only in the morphine state, and stimuli to the opposite forepaw delivered only in the saline state. Following this training, various test groups are examined after either withdrawal or continued morphine injections. In another study, rats are trained to bar-press for IV morphine; stimulation of one forepaw is paired with each morphine injection, and stimulation of the opposite forepaw presented at random. Various extinction and withdrawal procedures are used following aquisition of the bar press response. Brain responses to the paw stimuli are recorded from a number of brain areas throughout all phases of the experiments. A major aim of the data analysis is to determine any conditioned neural response which develops and is still present following withdrawal or other treatment. If some association of the neural learning system with drug dependency can be determined, then it may be possible to utilize specific blocking agents or treatment to reverse the learning component of addiction.